To your question: No, it is not necessary. You can put information, images, anything on category page. Note that the way to link to category page is a bit different to normal page.
Like this: [[:Category:Guilds|guild]] >> guild
That was more of a rhetorical question to bring up the question of whether we should actually keep this page. As you said, a category poage is just as good as a regular article for this purpose. And yeah, I've noticed that categories link a bit differently, just didn't know how exactly :D --Gsimenas (talk) 10:23, May 14, 2013 (UTC)